7. BREEDING OF RICE FOR RESISTANCE TO MAJOR DISEASES, PARTICULARLY LEAF BLAST

IN THE PHILIPPINES

Esteban C. Cada*

Introduction

83

Rice blast (Piricularia oryzae Cav.) is considered one of the most important diseases in the Philippines because of its serious yearly destruction on rice crops in some areas. Other diseases that affect our rice crop in the order of their importance are stem rot (Leptosphaeria salvinii Catt.), sheash rot (Sclerotium sphaeroides Nak.), bacterial leaf blight (Xanthomonas translucens (]. J. R.) Dawnson), and tungro, a virus disease.

Reyes (1952) stated that considerable damage has been caused by diseases, which was conservatively estimated to decrease the aggregate output by 5 per cent. Under extremely favorable soil and climatic conditions, the major diseases could inflict as much as 25 per cent or more damage, especially if the variety planted is susceptible.

The importance of diseases particularly blast and bacterial leaf blight in rice production cannot be over stressed. This is because, these diseases may become a limiting factor in the attainment of higher level of rice production per hectare through the use of greater amont of nitrogen. For rice plants fertilized at high rate of nitrogen may become susceptible to the disease due to very luxuriant growth.

Previous Work on Disease Resistance Realizing that the conventional methods of controlling the ravages of diseases which may

fall into (1) improved cultural practices and (2) use of effective fungicides are only pallative, plant breeders and plant pathologists have cooperated in studying the reaction of varieties to diseases.

Reyes (1952) reported that the results of his years of meticulous study and observation covering 18 diseases occurring in the Philippines on 52 rice varieties, showed that only \Vag­wag was resistant to blast. Certain varieties were liable to the attack of rice blast, stem rot, helminthosporiose, sheath rot, Fusarium blight, etc., while others swow varying degrees of resistance. Some of the varieties that possess notable reaction to certain diseases of more or less destructive nature are indicated below:

1. Stem rot (Lepthosphaeria salvinii Catt.) a. Raminad Str. 3 b. Apostol c. Guinangang d. Mancasar

2. Sheath rot (Sclerotiem sphaeroides Nak.) a. Elon-elon b. Raminad Str. 3

* Director, Maligaya Rice Research and Training Center, Philippines, He wishes to acknowledge the invaluable assistance of Mrs. Angelina B. Habacon, Mr. Ludovico C. Valencia, both Agronomist I, and Mrs. Lagrimas B. Salisi, Plant Pathologist I.

c. Guinangang 3. Brown linear spot (Cercospora ory.zae, Miy.)

a. l'vlancasar b. Rcanay c. Ra:cninad Str. 3

In a test for the reaction of 27 rice varieties that were considered resistant to blast in their countries, (Reyes, 1959) planted singly 21-day old seedlings of test yarietics in alternate rows with susceptible varieties at a distance of 20 by 20 ems. The were fer­tilized with ammonium sulfate at the rate of 150 kilograms per hectare.

Inoculation was done at two stages of growth. The first was done at thei~,- stage, and the second, during the heading period. At tillering stage, small amount ot inocu­hun consisting of and spores of the fungus together with small portions of the culture medium were placed between the common lower axils of the unfolded leaf and the youngest expanded leaf. The plants were sprayed with sterile vvater before they were covered with a humidity tent consisting of moistened heavy cheesecloth. At early heading stage, the incou­lum was placed at the hairy portion of the lowest node of the rachis of a emerged panicle. After each inoculum, the plants were sprayed with sterile water after which they were covered with humidity tents \vhich were kept moist to keep favorable and temperature fc,r rapid development of the fungus.

From this study, Reyes concluded that under the conditions provided in the lest, many of the varieties considered resistant to blast disease in their country of origin showed suscep­tibility. All the American varieties showed strong tendency for susceptibiiity to neckrot form of the disease. Of the eight varieties from Malaya only two were found resistant, and about one-half of those that came from Indonesia showed susceptibility to the disease.

He reported further that high percentage of infections were observed in varieties with ahuncbnt hairy growth around the neck or colla region of the panicle. Generally the long maturing varieties have greater chance of escaping the disease or prospect of recovery. There was aiso a positive correlation between relative humidity and infection; and a notable nega­tive correlation between percentage of infection and air temperature was observed.

Ou, in his paper presented during the symposium on the Rice Blast Disease held on July 7-12, 1963 at the International Rice Research Institute at Los Banos, Laguna, Philippines showed that Japonica (Taiwan) varieties with reactions of moderately susceptible to very sus­ceptible in Taiwan were found highly resistant in the Philippines. On the other hand, Indica (Taiwan) varieties that vvere resistant to moderately resistant in Taiwan were very susceptible in the Philippines.

Recent Studies on Blast Resistance

The results of studies on blast resistance were obtained at the Maligaya Rice Research and Training Center and other experiment stations from 1962-1965. 1. Method of Testing for Blast Resistance.

The present breeding program for blast resistance utilizes the techniques recommended by the International Rice Commission and revised by the Technical Committee for international blast program at the International Rice Research Institute in 1961. The technique works on the principle of providing the proper micro-climate and fertility in the seedbed for gro·wth of fungus.

The seedbeds of 1.2 m. wide and about 20 meters long were provided with the necessary level of soil fertility by applying well decayed compost and chemical fertilizer with a formula­tion of 120 kgm. or more of N and 50 kgm. P 20 5 per hectare. One half of the nitrogen and the whold amount of P 20 5 were applied before the seeds were sown. The second half of the

85

nitrogen \Vas applied two weeks after germination. Planting the varieties.

FiYe grams of each test variety, the susceptible and resistant checks were sown in 50 em­rows distaw·ed 10 ems. apart across the bed. Bombardment rows of a susceptible variety,

>Yere planted and after eyery two rows of test varieties. A resistant variety, Peta was after every ten test varieties between two rows of the susceptible check. Bom­barment rcws of the susceptible check, 3 on the windward side of the bed, tvvo on the other side and at both ends of the bed, were also planted at the same distance as the test ;-arieties across the bed (see Fig. 1)

"' "' U)

"' "' "' E "' "' C"! "' "' 00

"' "' "' ,..... "' "' "' "' "'

' i I I I I

j_j__ __ _

sssssssssssssssssssssssss sssssssssssssssssss sssssssssssssssssssssssssssssssssssssssssssss sssssssssssssssssssssssssssssssssssssssssssss

"' ........ "' "' "' ... "' ..., Testing

~~rJ) 00 ......... "' ...,..., <fj ~·>! (j) ....

...,....,"' "' _...,__,

"' "' '- "' ..., row-50

"' .......... "' ......... "' ...,..., lf; '"' "' .... ..... .... "' ...., ..... ., 01 .......... "' .......... "' ... "' ..... em long, .... ..... 00 ........ "' ..., ....

"' ........ "' "' .... ..., ..., ......... "' ......... "' .......... "' "' ... lOcm . .... ..... ..... , ..._,;, {/)

"' "' ;..,

apart

sssssssssssssssssssssssssssssssssssssssssssss sssssssssssssssssssssssssssssssssssssssssssss sssssssssssssssssssssssssssssssssssssssssssss

"'

_I

~ I

"' "' "' "' "' "' "' "' "' m

"' "'

I ~----------------------·__1

wind direction

Fig. 1. Diagram of a testing plot or seedbed

The seedbeds vvere kept moist all the time to provide the proper micro-climate in the seedbed for the development of the fungus. To enhance better infection a seedbed \vas plant­ed to the susceptible check two weeks before the test varieties were sown. Chopped infected leaves were also spread o;-er the seedbed after the seeds have germinated.

(2) Classification of disease reaction. The method of scoring disease reaction adopted by a committee that met at the Interna­

tional I-<.ice Researsh Institute was followed in the test for blast resistance. The symptoms and infection reaction are shown below:

Scale Unit

1

Symptoms

Only small brown specks of pin-head are produced on leaves, few or many, sometimes unrecognizable, no necrotic (collapsed cells)

Infection reaction

spot. Resistant (R)

Slightly larger brown specks, about 1/2 mm. in diameter, no necro-t'c spots.

Small, roundish, necrotic, grey spots about 1-2 mm. in diameter, surrounded by brown margm which is roundish or tends so be elliptical; the legions may be many, but leaves arc seldom killed from the infection.

Moderately resistant (MR)

813

Typical blast lasion, elliptical, 1-2 ems, long usually confined to the of two main veins, \Vith large, necrotic grey center and or reddish brown margin, usuF:.IIy relatively few on a leaf

than 5% of leave area is damaged.

5 :Vfany large blast as in group 4 or often and broader, the upper portion one or two of the leaves seedling of 4 or 5 leaves may be killed by coalescence of lesions the total area killed, however, does not exceed 25 ;'0.

t) Lesions as in Group 5, but are more in numbers; a few leaf-blades may be completely withered; the total area killed may reach 50%; ],;usceptibk the margin of tbe lesions often shows less brown color; more of yellowish or greyish brown.

7 Large, quickly expanding lesions, the margin of wbich is mostly of grey color with brown tinge; most of the expanded leave.s are killed but young ones remain 'leaf killing ranges from over 50~0 to complete death. '

2, International Uniform Blast Nursery Test The International cooperative uniform blast nursery test sponsored International

Rice Commission, F AO had the objectives of determining varieties that are resi~tam to dif­ferent regions of South East Asia.

The method of testing varietal reaction to blast previously discussed in this paper was used in this study. The varieties used in the test were considered resistant in their respective countries.

The final individual reaction of 109 varieties tested in one or two years, is pre8DJted in table 1. The lesions due to blast infection appeared about 17 days after the seeds \Vere sown, and the final rating for varietal reaction was obtained 34-40 days after

The data presented in table 1 shows that while the varieties in the test were considered resistant in their respective countries, a large number of them had shown or moderate susceptibility to fungal development.

Is is significant to mention that two of the Philippine varieties considered resistant to blast in previous test with the use of artificial inoculation were moderately to the disease when subjected under the new method recommended by the F AO.

A summary of blast reaction of varieties by countries is shown in table 2. The table shows that the entries from each cooperating country showed differences in reaction to the disease. Only 3 of the 9 varieties from Burma exhibited high resistance to the disease. Three of the ten varieties from 11alaya were susceptible, and not all the varieties from Japan and the United States, where varietal reaction to blast was studied more intensively than in other participating countries, proved resistant to the disease under Philippine conditions.

The fact that a total of only 67.83 percent of the resistant varieties from cooperating countries showed resistance to the disease under Philippine conditions may indicate that more virolent physiologic strains of blast organism than those present in the countri:cs of origin may be present in the Philippines. Ou (1966) stated that some varieties seem able to differentiate general race groups by geographical regions. 3. Test for I<esistance to Blast of Established Varieties and Hybrid Strains in Different Stations

The cooperative test for blast resistance was undertaken by the Plant Protection \Vorking Group of the Recommnding Committee of the Philippines Seed Board lead Dr. Ofelio R. Exconde of the U. P. College of Agriculture. The objective was to e\'aluate the reaction of Seed Board recommended varieties and promising hybrid strains to blast disease and determine those that are consistently resistant over a wide area.

The results presented in table 3 obtained in four stations indicate that in the ilrst group,

consisting of varieties in the advanced test in which 13 Seed Board recommended varieties

87

were included, only eight out of 29 entries were found resistant to the disease. Of the resistant varieties 6 were recommended the Seed Board for general planting.

In the test, consisting of 29 and strains, 9 strains showed resistance to the disease; the rest were which were susceptible.

It is significant to strain from a cross between

out that among the 20 and Peta, was

\'arieties, only Panpet 120. a s1x were susceptible and the

rest were moderately susceptible.

The reactions the different varieties differed in some cases in the four stations. This differential reactions of varieties in the different locations may be attributed to differences in the prevailing local climatic conditions and the existence of different races of Pi'ricularia or:_vzae (~av. in the four stations. In fa.ct ()u, (1966) noted that the races differ

in the different of the country, the distribution of which may be seen below.

Regional Distribution

1. Northern Luzon Central Luzon

cl. Soutbern Luzon 4. Bic61 5. \Vestem Visayas 6. Eastern Visayas 7. ·Mindanao

See appendix 1.

No. of races identifred*

4 10 12 5

!7 ()

9

4. Reactions of Hybrid Lines from Pedigree and Modified Bulk Selections to Blast In this study two groups of hybrid lines were tested for leaf blast resistance. The first

group consisted of lines selected by the pedigree and modified bulk methods from the same cross, while the second consisted of pedigree and modified hulk selections.

(1) Reaction of lines from the same cross selected pedigree and modified bulk methods.

The reaction of 404 lines from three crosses in the F 6 and F 8 generations selected by the pedigree and bulk methods are presented in table 4. It may be seen from the table that of the 69 lines selected by pedigree, 51.'19 per cent were resistant to the disease, 40.12 per cent, moderately resistant while only 2.77 and 5.60 per cent were moderately susceptible and sus­ceptible, respectively. On the other hand, of the 335 lines selected by the modified bulk method only 19.3 per cent were found resistant. Greater percentages of susceptible and mod· erately susceptible lines were observed from the bulk method of selection than from the ped­igree method.

This observations seems to indicate that pedigree method of selection is more effective for disease resistance than the modified bulk method.

(2) Reaction of hybrid lines from crosses with one common parent. In this experiment, 9 F 4 crosses under pedigree selection with a total of 568 lines were

tested for leaf blast resistance. Another group consisted of 2,180 lines selected from bulk planting in the F 6 and F 7 gen­

eration. In both groups, either the female or male parent was common in some of the 24 crosses.

The data presented in table 5 show that F 4 lines from the same female parent under ped­igree selection differed in reaction to blast as expressed by the great difference in percentage of resistance and susceptibility. This is exemplified by the crosses Y ab-yabi x Taichung 71,

K8

and Yab-yabi x B-E<l in which 43.36% of the lines in the former were resistant while only This trend was also true in 6 other combinations in which

vvas used as a common parent in two crosses. 24 crosses in the F 6 and F 1 generations under the modified bulk method of selec­

tion, it IS interesting to point out that in three crosses in which one common variety was used the re;>ction of the selected lines to blast differed markedly. In the cross Inilang-ilang X

all the lines were susceptible; in the cross Inlang-ilang x Nagpunit, 40 per cent were resistant, while in lniland-ilang x Sampay Bakud, only 7.5 per cent of the lines were resistant. And in three crosses in which Rexoro was used as a common parent, the cross, Rexoro >< produced lines in which 811 per cent were resistant. On the other hand, in Rexoro x l\1ilfor 6 only 2 per cent \vere resistant while 40.85 per cent and 47.78 per cent ·were moderately and susceptible, respectively.

The differences in reaction of lines selected by the pedigree and modified bulk methods ir; which one variety was used as a common parent may indicate the differences in the desirability of varieties as parents in varietal crosses.

Reaction of Varieties to Other Diseases

Like in d1e on the reaction to blast disease, the data presented m the reaction of Seed Board recommended varieties and promising hybrids to other diseases were the results of the cooperative efforts of Plant Pathologist and Plant Breeders in the Bureau of Plant Industry and the U. P. College of Agriculture. 1. Reaction of varieties and promising hybrids to leaf blight

This experiment was conducted in the U. P. College of Agriculture and two experiment stations of the Bureau of Plant Industry to evaluate the resistance or susceptibility of rocom­mended varieties and promising hybrid strains now under for yield.

The method developed by Goto (1965) for evaluating resistance of rice varieties and species of wild rice was used by the cooperating researchers in each station.

The results presented in table 6 show that of the 78 varieties in the test only three vari­eties vlere resistant in the three stations; namely, Norelon Str. 340, a Seed Board recommend­ed variety, Tainan 3, a promising introduction, and Sungforbes 101, a glutinous variety.

The other varieties exhibited variable reactions in the three stations in which they were tested. In some cases varieties were found resistant in two stations, but susceptible in another station. In other instances, varieties were susceptible in two stations but resistant in one sta­tion. Based on the average reaction in three stations, four varieties from each group were resistant to the or a total of 12 out of 78 varieties that \vere studied.

As bacterial leaf blight is becoming an important disease in the country due to increas­ing amount of fertilizer applied in the rice fields, breeding for resistance to this disease has been expanded. Using resistant varieties as parents, some 49 crosses now in the Fe genera­tion are being studied at the Maligaya Rice Research and Training Center aside from the tests being conducted on promising hybrid strains. 2. Reaction of Varieties and Promising Hybrid Stn:ins to Tungro Virus Disease under Field

Conditions, 1965-1966 Briefly, it may be stated that according to Ou and Rivera* Tungro is probably the most

wide-spread and mcst important virus disease of rice in the tropics. It is transmitted by Ncphottetix apical is :tv1atch. The most important diagnostic symptoms of the disease are: (1) yellowing of leaves, depending upon the resistance of the variety, (2) stunted growth espe-

* Ou, S. H. and C. T. Rivem. Virus disease of rice in the Philippines nearby Countries. Paper present­ed during tbe lOtb meeting of the ·working Party on Eice Production and Protection, International

Rice Commission, held in Manila, Philippines on March 3-10. 1964.

cially in susceptible varieties, (3) affected

ing of affected plants is somewhat reduced.

produce few and small and

89

tiller-

The field test of varieties for reaction to

al.* in three locaticns C\Ianila, Lanuna and

disease w<Js conducted et ·where infection ovserved to be

ser1ous. The v;uieties and hybrids used in the test were tested under green con-

ditions and were rated as resistant and medium resistant. The observations en the reactions

of the 25 varieties to tungro under field conditions shown in table 7 indicate that the average infection in Manila was and in Pangasinan, :-36.54 per cent. This

average infection in the t\vo places may indicale '' high number of that were earners of che Yirus disease. In fact as high as infectinn on BPI--76 was obsernxl in

Manila <md 100 per ct nt on \V agwag in It mcty be out further that the varieties that showed high infection in one

had aiso infection in other places as in the case of BP176, Nm:elon Str. 340, and vv-.-ag.

Based en the average percentage in three it may be seen that !lot a 111 the under field ,:·,ondition \vas resistant to tbe disease. Out of the 25 test varieties,

four were mediurn resistant while the rest were either medium or

to tungro nrus disease.

Summary

This report covers some results of cooperations studies on the reacuon to nee of established varieties, promising hybrid strains and hybrid lines selected the

modified bulk methods. H.eactions of varieties and promising strains to bacteri;c<l leaf and tungro virus disease under field conditions are also reported herein.

In the cooperative international uniform blast nur.,;ery test sponsored by the International Rice Commi:ssion and now coordinated by the IRRI, only 67.83 per cent of the test varieties kno·wn to be resistant in their respective countries of origin were resistant to blast under Phil­

ippine conditions, indicating the possibility of the presence of more virulent strain or l·ctce of

the organism in the Philippines. Only three of the 9 varieties front Burma exhibited high registance to the disease; three of the ten varieties from J\1alaya were susceptible, and not all the varieties from Japc:n and United States where varietal reaction to blast was studied more intensively than in other countries resistant to the disease.

Established vil-cieties and promising hybrid strains of rice tested in different

stations showed variable reactions to blast disease. This shov:s the existence of different phys-

iologic races of bb.st m the four testing stations.

The reactions of lines, selected by the pedigree and modified bulk showed that greater percentages of susceptible and moderately susceptible lines selected by the bulk method were observed. These obseryations seem to indicate that pedigree method is more effective for disease resistance than the modified bulk method,

Lines selected by the pedigree and bulk methods from crosses in which

used as a common parent showed marked differences in reaction to blast disease:. was

These dif­in varietal ferer,ces may indicate differences in the desirability of varieiies as

crosses. The study of 78 varieties for bacterial leaf blight resistance show that three varieties

* Bergonia, II. T., Cax!os A Calica, C Baniqued and E. P. NoYero. Te;t on the re ·ct;on of certain Seed Poard rice varieties and pro1nising bybrids to tdngro under field conditicnY·-i. ~\?\Iirn-cograp l1ed). Presented during the 14th Annual Rice and Corn Production Conference, held in tl:e ;;pi on April ll-15, 1967.

90

resistant in three stations. These variety were Norelon Str. 3·10, a Seed Board introduction and Sungforbes 101, a glutinous

variety The program on

Sungsung and BBI-76. for resistance to bacterial leaf blight ;,vas

45 F 2 crosses are now underr study. The test on the reatsion of 25 varieties to virus under field conditions in three

locations showed in percentage of infection in the different However, there

were indications that a that showed perccnt2.ge in one place had also infec-tion in another Based on the average percentage of infection in three not a

Country of

Origin

Dunn a

Ce:,rlon

France

Tlongkong

India

Japan

of 25 in the test shovved resistance to the disease. I-loYvever, four var1et1es

resistant.

'l'able 1. Reaction of individual varieties from different countries to fungal development.

No. of Rating \Tarietjes --~~------

Var. 1%2 19(i3

9 l_ A 3(i-:3 5 [} ., A 56-11 5 3. B-35-2 ~) ;:)

4. B 401 f) 5 5. B 404 4 ;)

r,, c 33-18 l 1 ry c t1li-15 1 1 I.

8. c 30-32 :\S 5 9. D 254 1

5 10. H-4 l 11. H-5 2 12. H-105 l 13. H-501 2 1 14. Murungakayan 302 1

4 15. Cesariot 4 l Hi. Fanny 4 2 17. Arlesienne 2 18. Cigalon '1

,J NS

4 19. Fa Yiu Tsai 1 1 2(} Kam Bau Ngan * 21. Lo Shu Ngar 2 l 22. Pak Huk Chai Mei 2 l

10 23. Ninnidhan 2 24. PTB-10 l 25. AC 2250 * 26. Hybrid I * 1 •)ry ~I. Hybrid II * 1 28. S-67 1 l 29. C0-4 1 1 30. C0-25 1 l 31. CO-Y NS 1 32. C0-13 NS " a

10 33. Norin 1 1 1 34_ Norio 17 1 1 35. Kon-go l 1 3'' \), Homare-nishiki NS l :n. Norin 22 NS 2 ~38. Kanto 51 NS l 39. Pi No. 51 NS 3 40. Usen NS 4 41. Cboko-to NS 1 42. Tadukan NS 1

Final .Rating

Grade H .. eaction -'---"--- ---------

5 s ;:) s 5 s 5 s 5 s 1 l-IR l I-I H .. 5 s 1 HR

l Im. I(

HR 2 H.

HR

3 iviH. 4 MS 2 R 3 MR

1 HR

2 R ')

I~

2 I< 1 IIR

1 HR 1 HR

HR 1 HR 1 rm 1 HR 3 MR

1 I-IR HR

1 HH. 1 HR 2 R

HR ., ,) MR 4 l\1S 1 HR l HR

------·----------- ______ ._ -------·~--~--.-'----~-----·- --------·~------- ----.-----~---~-~---

91

Table L

Country of No. of Rating Final Rating Varieties

Origin VaL 10/'C) ~-u~ 19Ei:l G-rade H .. eJ .. ct1on

Malaya Padang 'Trenggaun 22 1 l llR Sepilai Kechi] l NS HR Puteh 1 4 ·) MR ,,

4f). Subang In tan 117 4 4 MS 47 Mayang Sagumpal 2 1 ') R 48. Serendah Puteh * 49. Anak Nag a 2 ) :VIR " 50. Seri Raja 3 4 4 :VIS 51. Mayang Ebos 80 :.; 4 :V1S 52. Radin Kuming 4 l\IS 5:1. Radin Siak 34 1 R

Pakistan ll 54. Dular 1 HR 55. Dharial 4 2 ;) MR 56. Has hi Kalmi 1 l IIR 57. Kataktara 1 l HR 58. KP.F.G 1 1 l HR 59. Marich Bati 1 1 IIR (iO. Panbira 2 l R CL Latisail C1 4 0 s 62. Patnai 63. Tilokkachari 5 4 5 .:.·

·' 64. Daaea-31 5 NS 3 s Portugal 65. Stirme 1:-36 5 ;_) s

56. H.ina'tdo Bersain 6 vs Philippines 14 67. Binicol 4 MS

68. Macapilay Pus a 2 1 R 69. Pinursigue 3 ,_)

" MR 70. Dinafor 6-50-45-A3 4 3 4 :'dS 71. FK-135 2 ._,

,) 2 R 72. BPI-76 1 2 2 R 73. FB-120 2 2 H 74. FK-170 1 1 ~viR 75. B-E-3 1 2 :! R 76. FB-124 1 H 77. Rarninad Str. 3 3 2 2 H. 78. Wagwag 2 1 2 HR 79. Peta 1 1 l FIR 80. BPI-121 1 HR

Senegal 6 81. R-67 1 1 HR 82. R-75 2 1 '1 R 83. Iguape Gatelo 4 2 3 MR 84. Jappeni Tunkungo 4 1 :_j MR 85. E-425 4 1 3 MR 86. RT. 1095 S-2G 4 2 :3 MR

Taiwan 15 87. Chia-mmg Yu 280 2 2 R 88. Chia-nung 212 3 2 2 R 89. C-115 2 1 2 R 90. Taichung 181 l 1 1 HR 91. Taichung 182 1 1 1 HR 92. Taichung 183 1 1 1 HR 93. Taichung line 48212 1 1 l HR 94. Taichung line 4772o 1 1 1 HR 95. Kaobsiung line 135 1 1 HR 96. Kaobsiung line 137 1 1 l HR 97. Kaohisung line 164 2 1 2 R 98. Taisung Yu 83 2 1 2 R 99. Taichunh (Native) 5 1 ') MR ,)

100. Ber-me-fen 4 " 4 MS D

101. Pai-Kan-tau 2 l 2 R Tailand 3 102. Nahng Mon S-4 1 1 1 HR

103. Leuang Yai 34 1 1 1 HR

92

Table 1. \Ctmt'cl)

Country of No. of' Rating Final Vatieties

Origir Var. 1962 1963 Grade

104. Pak Lecwd III 1

U. S. 9 105. c L l ~ ! L

1()(). c L 1 107. c L 4 2 ~)

108. c L 4 2 3 109. c L 4 1 3 llO. c I. 1 1 1 llL c I. 2 2 112. P. L 3 1 2 11:1 P. L 201902 1 1

!\Tote: *-Did not genninaie ME- Moderately resistant NS- No. seed MS -Moderately susceptible HR-Highly resistant S- Susceptible P- Resistant VS- Highly susceptible

Table 2. Summary of the reaction of varieties by countries

L

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

n 14.

A.

1.

2.

:3. 4.

-- -------- ---------- < --~------------------------------------- <

No. of Grade of Resistance to Fungal Development Countries

Var. HR MR MS s

Burma 9 c) G

Ceylon 5 3 2

France 4 2 1

l-Iongkong 3 l 2

India 9 7 1 1

Japan 10 7 1 1 1

Malaya 10 3 2 2 ::l

Pakistan 10 5 1 1

Philippines 14 4 7 1 2

Portugal 2 1

Senegal 6 1 l 4

T·aiYYan 15 6 1 1

Thailand ') ,, 3

US. A. 9 4 2

Total 109 48

Per cent 44.03

Table 3. Reactions of rice varieties to blast at different stations during 1965 wet season.

AC 440 DR 2fi0* R MR R R

AC 224ii Mas s s s s Peta* MR MR R R Tjera Mas* s s s s

Eating

Reaction

HE

HR HR MR MR MR HR R R HR

---·--------

vs

1

l

0.92

Final

Reaction

R

s MR

s

Table 3. (Cont'd)

Entries

5. HR-38

(), Rading Kling

7.

8. BPI-76*

9. Milbuen I

10. C-18-74*

11. Milketan ti

12. Pamil I

13. Taimil 3

14. C-1:l

15. Bengawan*

Hi. FK-178A*

17. Nang 1"'hay*

18. Norelon Str. :340*

19. RP-44

20. RP-4:'l

21. FK-178A*

22. FB-7GA

2:3. FB-7GC

24. FD-76-6-3

25. TPBKF-16-1

2ii. S. K. 36 Str. 482*

27. Raminad Str. ;)*

28. BPI-121*

29. B-E<l*

B. Varieties in tbe General Test

1. Milbuen 19

2. Tpmil 29

:l.

4. Chianung 242

5. Tainan-iku No. 486

6. Shinchiky-iku No. 74

7. C-16

8. BPI-76 (Bicol Sel.)

9. PI-215, 93fi

10. Taicbnng (native 1)

11. A3-47-2

12. IR3-!i6

13. IR8-24li

14. M527-9

15. RPA-4

16. RP-9

17. RPI-46-l

College

MR R

MR R R s R MR MR R

R

R

s MR IVIR

R R

R

R

:viR

MR MR R MR

R

3

s s MR MR R R

R

MR R

R

MR R

R

R

Stations

:'viR

MR s MR R

s IvlR

s

s MR MR s

:tviR

MR l\1R

MR MR s s MR s

MR MI~

s

s s s MR s s MR MR s s R

MR :rvm

Iloilo

H.

s R

R

R

s R ~1R

1IR

R

R

R

R

s R

R

11R

s s s s MH

s R

s R

R

H

MR MR R s MR s R

R R

s MR

93

Final

-i,{~ligaya dJ Reaction

H.

IvlR

R

s R

R

R

R

R

s

R

R

R

R MR ?viR

R

MR

I{

s R

Mr No

gern1.inati,-;n R

R

R

s

R l{

R

R MR

R

lvlR

:vm MR R

s R

MR R R

s MS

l\lR

~IS

l'viS

MR ~IS

R

MR s ?viR

MR :\1R

.\IR

MR MS

Iv1R MR MR \IR

R rvm MR

94

Table 3. iCont'd)

Final Entrres

floiio C,t Maligaya Reactoon ---------~ --------------------- --·-----·--------·-·

18. MIFB-318-1 R MR R R R

19. '\HFB-·318-2 R MR MR 1~ MR

20. MIFB-54-l R R R R R 21. MIFB-150-4 MR s R R MR 22. MIFB-44-1 R MR R R R 23. RPP<ll-3 MR s s R MR 24. FB-76-8-1-2-1 R MR R R I~

23. MIFB-2iti-4 R R R R R

2!'i. Tainan q ,) R R s R MR

27. A:J-47-:J MI~ s s s s 28. IR8<~6 R s R R MR 29. IR9-60 R R R R R

c. Glutinous Varieties:

lnagubatan R s R R MR 2. Pinutyukan s s MR s s 3. Serena s s s s s 4. Binundok s s s s s 5. Malagkit Sung,;cmg s s s s s (i. Pan pet c· ),.) R MR s R MR

7. Morforbes 120 R MR R R R 8. Pantje lUi MR lVIR s R MR

9. Morforhes 25 s MR s R MS 10. Sentje 117 R MR s MR MR 11. Pan pet MR MR s R MR 12. Morforbes 23 MR MR MR R MR 13. Morforbes 122 MR MR MR R MR 14. Sungforbes 101 s s s s s 15. Morforbes 22 MR MR s MR MR 16. Sungforbes 59 MR s s MR MS 17. iviorforbes 119 R R s R MR 18. Morforbes 55 R R s I<. MR 19. Pen pet 68 R MR s R MR 20. Sung forbes 49 s s s s s

~---·------------------~----~----- -·-----·---

* Seed Board recommended varieties a) Conducted by 0. R. Exconde, et. al. b) Conducted by 0. Lawas, et. al. c) Conducted by F. M. Olivares, Jr., et. al. d) Conducted by P. B. Romano. et. al.

Table 4. Reaction of selected lines from pedigree and modified bulk selections from the same crosses.

Method of Selection

Pedigree Ffi

Bulk

Pedigtee Ji'()

Bulk

Pedigree FS

Bulk

MA-3-26 x FB-76-2-2

-do-

Binirhen :366 x RPP-17

- do -

(Rexoro x Purple Leaf In tan\

- do -

Pedigree (Average %)

Bulk selection (Average %)

1\'ote: Figures in parenthesis are percentages.

13

35

44

100

12

200

69

3~-35

(0) ()

(34. 3) 12

(50.0) (0) 22 0

(7.0) i

(31. 0) (16. 0) 7 :31 16

css. :l3) I (33.3) (8. :1:3) 7 4 1

(50. 1) (32. (13. 0) 102 26

51.49 40. 12 2.77

19.3 27.8 21. 1

Table 5. Reaction of hybrid lines with one common parent. (1) Pedigree

Crosses MR MS

----------'" --------- ------------~--- ~---------

(30.8:3) (22. 34) L F 4 Fortuna x BPI-76 94 29 21

(7.57) (:39. 39) (34. 84) 2. F 4 Fortuna x FB-·110 66 5 26 23

(43.36) (3:1. 63) (l. 77) i

:i. F 4 Yab·yabi x Taichung 226 98 86 4

(12.50) (25.00) (29. Hi) 4. F 4 Y ab·yabi ;, B-E-3 24 ., 6 7 ..,

(18.18) (63.63) (9.09) 5. F 4 Minangan x B-E-3 44 8 28 4

(2. 77) (54. Hi) (34. 72) !

6. F 4 Patax(RPA-49xFK-133-2) 72 2 39 25

(29.54) (54. 54) (11. Hi) " F 4 Peta x (Ma-3-26 x FB-76-2-2) 44 13 24 5 /.

(49.18) (44.25) (4. 92) 8. F. BPI-76 X (RPA-49 X FK-133-2) 61 30 27 :.;

(58.00) (37.01) (5.07) 9. F. BPI-76 X (MA-3-26 X FB-76- 137 80 50 7

2-2) 568

Note: Figures in parenshesis are percentages.

95

s

(7. 7) l

(45. 7) 16

(9. 1) 4

(46.0) 46

(0) 0

(3.5) 7

5.60

31. 7

--------·-

s

(35. 10) 23

(18. 18) 12

(5.31) 12

(33.33) 8

(27. 27) 12

(8. :-33) 6

(4.54) 2

(1. 64) 1

(0) 0

96

Table 5. Reaction of hybrid lines with one common parent.

\2! Modified bulk

Crosses

F 6 BJnirbe:1 X RPP-10

3. F 5 l\11-50 x ?v1I-71 x I\ianp;arcz

::J. Fn ~~H-·L' > :\U-72 x Rexoro

9. F, Inilang-i!an.'~ )< ::\a~ptmit

10. F, RPI-:'4 <.\L\.-l:J-1:2

11. F, RPP-4'2 ~L-\-13-12

12. F, RPP--19··. .\lA-lC)-12

n F, RPP-49 '>, I\.PI-72

14. F 6 ~.1A-:J-:2:i FB-76-2-1

15. F 5 iMI-50 .~II-71) FB-7G--2-l

16. F 7 Rexoro > Milfor 6(2)

17. F7 Rexoro:<Apostol

18. F 7 Rexoro x !Purple leaf X In tan)

19. F 6 MA-:'-2'1 >- FB-76-2-2

20. F 6 MA<l-26 .<lv1A-1-10

21. F 6 MA-15 >; Azucena

22. F 6 Ml-56xAzucena

23. F 6 IBP-15>:IBP-24

24. F 6 IBP-15>dBP-lll

Note: Figures in parenthesis are percentages.

Total

70

~)()

:~o

20

110

GO

140

1,10

50

50

350

100

200

60

140

90

55

30

2,180

(7.0) 7

(ll.ll) 1()

0

(7. 5) :3

(40. 0) 8

c;o.

(78.

(9. 28) l:i

(7. 14) 10

(20.

(:36.0) Irl

(2.

(84. 0) 84

(51. 0) 102

(0) ()

(10. 0) 6

(4.28) 6

(18. 89) 17

(:~. G:-l) 2

(20.0) f)

MR

c::n;,o) ,)l

(20. (f)

14

(:24.

()

(:36.

(26.0) f)

(11. 0) lJ

(2(). 0) 7

(46.0) 27

(12. 14) 17

(23.7) 7

u

,:_;z_ o_ : l

(lO. o) ;)

(~i. o~~

-~J2. 14) 46

(14.

(12 .•

(li. 6) •)

!J5. 0) 9

0) 7

:w. 0) 5

~2.0) 2

c:t o) 7

(51. 42) n<) I~

(6,67) 6

(70. 91) 39

(50.

97

Table 6. Reactions of rice varieties to bacterial leaf blight at three stations during 1965 wet season.

Stations Final Entries . ~-- ------ ·--- ~-

c) College San Mateo Reaction ·-'"·-- -------~-------~-,~---

_.'L Varieties in the Advanced Test:

1. AC/440 Dr. 260 R R MR R

2. AC/224 Mas R s 1\IR MR

3. Peta s R MR MR

4. Tjere Mas R R MR R

5. HR-38 R R MR R

ti. Radin Kling R R MR R

7. D/52/37 R R MR R

8. BPI-76 s R MR MR

9. Milbuen I R R s MR

10. C-18-74 R R MR R

11. Milketan 6 R s MR MR

12. Pamil I R R s MR

13. Taimil 3 R R MR R

14. C-18 R R MR R

15. Bengavvan R R s MR

16. FK-178A* R s MR MR lry

/. Nang thay R s MR MR

18. Norelon Str. 340 R H. H. R

19. RP-44 R R s MR

20. RP-43 R R MR R

21. FK-178B R s s MS

22. FB-76A R s MR MR

23. FB-7GC R s s MS

24. FB-76-6-3 R s MR MR

25. TPBKF-16-1 R s R MR

26. SK-36 Str. 482* R s MS

27. Raminad Str. 3* s s MR MS

28. BPI-121* R s s MS

29. B-E-3* R s MR MR

B. Varieties in the General Test:

1. Milbuen 19 R s MR MR

2. Tpmil 29 s s MR MS

3. A/29/20 R s MR MR

4. Chainung 242 R R MR R

5. Tainan-iku No. 486 R R MR R

6. Shinchiky-iku No. 74 R s MR MR

7. C-16 R s MR MR

8. BP!-76 (Bicol Sel.) R R MR R

9. PI-215, 936 R s MR MR

10. Taichung (Native) R s s MS

11. A3-47-2 R s MR MR

98

Table 6. (Cont'd)

Stations Final Entries

Reaction ~-~-- ---- -,~--- - -~-------~--·------- -- ---·--·-----~----~--

12. IR.3-6() MS 13. IR.S-246 MS 14. M527-9 MR 15. RPA-4 s :V1S lG. RP-9 R s s MS 17. RPI-46-l R s MR MR 18. MIFB-318-1 R s MR. MR 19. MlFIHll8-2 R s R :VIR 20. MlFB-54 R s R MR 21. MIFB-150-4 R s MR. MR 22. MIFB-44-1 R s MR MR. 23. RPP-31-3 R. s .MR MR 24. FB-7Ei-8-1-2-1 R s MR MR 25. MIFB-266-4 R s :viR MR. 26. Tainan 3 R R. R R 27. A3-47-3 R s MR MR 28. IR8-:3G s s MR :VIS 29. IR9-60 s s R MS

c. Glutinous Varieties

1. Inagubatan R s s MS 2. Pinutyukan R s s :V1S 3. Serona R. s MR :VIR 4. Binundok R R MR. R 5. Malagkit Sungsong R R MR R 6. Panpet 63 R s s MS 7. Morforbes 120 R. s MR MH. 8. Pantje 116 R s MR. MR. 9. Morforbes 25 R s MR MR

10. Sentje 117 R s MR MR 11. Panpet 64 R s MR MR 12. Morforbes 2'' ,) R s MR MR 13. Morforbes 122 s s R MS 14. Sung forbes 101 R R R R 15. Morforbes 22 R s MR. MR 16. Sungforbes 59 R s R MR 17. .Morforbes 119 R. s .MR MR 18. Morforbes 66 R s R MR. 19. Pinpet 68 R s MR MR. 20. Sungforbes 49 R. R MR. R

------- --------~--------------~------ ---------~--------- ·--- -------------

a) Conducted by 0. R. Exconde, et. al b) Conducted by F. M. Olivares, Jr. et. al c) Conducted by 0. Lawas, et. al

Table 7. Reaction of rice varieties and promising hybrids to "Tungro" under field conditions, crop year 1965-66 a)

(Infection in percentage)

Test Locations Average Variety

Manila (BPI) Laguna Pangasinan Infection ~---~~------------

1. B-E-:o 50.00 10.0 44.29 47. 14

2. Bengawan b4.45 (*' . ) 3.19 34.82

:1. BPI-7b 98.85 11. 50 92.3() 67.57

4. BPI-121 85. 35 19.50 4b.40 50. ,u 5. C-18 69.00 11.00 49.84 4:3. 28

G. Ncmg Thay 74.20 14.00 68.89 52.36

7. Norelon 340 98.80 2S.50 68. 18 i3:3. Hi

8. Peta 56.20 6.00 7.08 23.09

9. Tjere Mas 40.80 0.50 14.49 18.59

10. AC440 Dr. 260 80. 10 21.50 79.76 60.25

11. i\!29/20 50. 75 7.50 35. 39 31.21

12. AC224Ei Mas 55.50 4.00 19. 14 26.21

13. C-13 30.60 1:3. 00 (*) 22.05

14. C-Hi G7.55 5.50 (*) 36.52

15. Earlblurnil 88.25 13.00 29.72 43.65

16. FK-178A 61.55 7.50 29.41 32.82

17. Milbuen 19 59. 20 11. ()() 44.07 38.09

18. l\1ilketan 6 54.65 5.50 31. 26 :lO. 47

19. Pernil 64. 15 8.00 :37.66 :3fi.fi0

20. PA-2 5:3. 2:) 12.50 18.56 28.08

21. RP-9 55.55 13.00 10.57 26. 37

22. RP-44 5:3. 30 G.OO 7. 14 22. 14

23. RPA-·4 48.80 18.50 1ii. 50 27. 27

24. Tprnil 19 82.00 8.00 37.60 42.55

25. \Vagwag 94.80 (*) 100.00 97.40

Average 65.80 11.02 36.04 ------- -~-----~ --------~-~~--- ------------- --------··~-

(*) Destroyed by rats.

99

Reaction

s MR

MR

MS

MS

l'vlR

MS

MS

MS

MS

MS

MS

MS

?vfS

MR

MS

MS s

a) Reported by H. T. Bergonia, C. A Calica, C. Baniqued, and E. P. Novero during the 14th Annual Rice and Corn Production Conference at the Bureau of Plant Industry, Manila on April 11-15, 1967.

Differential Variety

Kataktara AD 2

CI 5:)02

Chokoto

Co 25

Wag-wag

Pai-kan-tao

Peta

Race

Raminad Str. 3

Taichung T-C-W-C

Lacrosse

Cl 8970 (Straw)

Khao Tah Haeng

No. of isolates

Regional Distribution:

Northern Luzon

Central Luzon

Southern Luzon

Bicol

Western Visayas

Eestern Visayas

Mindanao

Appendix 1. Pathogenic races of piricularia oryzae of the philippines based upon tentative differential varieties selected in the philippines

! ! ~ ! ~

R R R R

R R R R R R R R R R

S R R R R

R R R R R

R R R R R

s s s s s R S R R R S K R R S S R R S S R S S S S

s s s

R R R R R R R S R R R S s s S R s s s s s s s s

R R R R R R R S M R

R S S S S R s s s s s s s s s s s s s s s s s s

R

R R s s R S R R s s s s s s s s s s

R R R S R s s R R R R s s s s s s s s

R

S R R R s s R R s s s s s s s s s s

R R R R R R R R R R R R R R R R R R I< S R S S S S R 1{

S S S R s s s s s s s s

R R R

R I{

R I{

R

s s

R R R R l(

R R R R R R l( R

R R R S s s

2 3 5 7 1 2 2 1 4 9 8 1 7 2 (j 11 3 5 5 8 3

1 - 2 1 1

1 1

1 2 3

1

2 1

1

1

fi 1

1 1

2 5

1

3

:l

l

l

3 2 2 1 2

4 4 - 1 2 2

2 1 ') 4

S S R S R. M'

R R R S M R

R I< R R R H s s l'{

s s s S S I< s s s

z ? 0 ,.,.,

"' 0

[ (!> U<

1 1 i Total 100

1

9

Hi

27 (i

21

1'!

9

z ? 0

HH-, (D Ui H

'D "'

8-. ffi <: ........ (l)p_.

'< 0 ~ r!. ~· i:h §B.. r.n

§"' s

4

lO

12

5

17 (j

9

,_. C> 0

101

Discussion

S. Okabe, : Regarding the comparison between pedigree and bulk methods shown m table 4, could you suggest any reasons why the difference has resulted in the later genera­tion? In the pedigree method, did the selection procedure include any artificial pressure in respect to blast resistance ?

Answer: It may be pointed out that both pedigree and bulk methods of selection are being used in the improvement of rice at the Marigaya Rice I<esearch and Training Center. For the pedigree method, individual plants were selected every year for such characters as maturity type of panicles and type of grains, shatterability of grains, and lodging character, as 'Nell as resistance to pests and diseases. In the bulk method, selection of individual plant wns done in the generation.

'fhe high perct:ntage of resistant pedigree lines compared with that of the bulk selections may be due to the yearly selection of superior plant type within the selected lines which were free from disease infection. In the bulk method individual plant selection was made only in the when the lines selected were tested for blast resistance in the F 6 and later generations.

There vvas no selection made based on artificial inoculation before the pedigreed lines were compared vvith the bulk selected lines in the test in the generation.

In the F 8 generation, the high percentage of resistant bulk lines may be due to individual plants selection made in the F 6 generations before were tested for blast resistance.

T. K. Van, Malaysia: You stated that in the test on the reaction of 25 varieties to Tungro virus, these were indications that a variety that showed high percentage in one place had also high infection in another place. vVas any observation made regarding the leaf hopper populations between these two places.

Answer: to the 2.uthors of the report, the places were selected for study of the disease because of the recurrence of the tungro disease in these places. vVhile they did not mention specifically the extent of population of the leafhoppers in these places they pointed out that crop failures were observed in these places. Since no control measure against the leafhoppers were done during the experiment, and because of the recurrence of infection in these places it appears that the population of insect vector was sufficient to cause crop failures.

D. N. Srivastava, India: Could you kindly elaborate the method of to bacterial blight at the ~l centers.

rice varieties

Answer: A uniform method of nee varieties for bacterial leaf blight resistance ·was adopted \vorkers in the three experiment stations. The method involved the use of short pins nwunted in two rows on a rubber stopper which is attached to the thumb by a rubber band. A of cork covered with cotton and cheese cloth soaked in bacterial sus-pension of X. oryzae is attached to the middle linger. The middle of the leaf of plants to be inoculated is placed betvveen the pine and cork which are slightly against each other so that the inoculum from the corlc wrapped with cotton and cheese cloth enters rhe vascular bundles of the leaves after the rubber stopper with the pins is v.'ithdrawn.

Twenty-days after inoculation, the flag leaves that were inoculated are examined. In very susceptible varieties, the lesions may extend toward the base and tip of the leaves. On re­sistant varieties, the downward movement of lesions may be limited to 1.5 ems. from the point of inocolation and for highly susceptible varieties lesions may be from 15 to 20 ems.

H. M. Beachel, U. S. A.: To improve efficiency of bulk method for blast resistance not subject seedlings to natural blast infection by growing in a blast nursery?

Answer: The suggestion to subject the seedlings to natural infection by growing them in

102

a blast nursery plot to improve the bulk method of selection, is well taken. The method, if continued from the F, seedlings up to the F 5 generation when individual plant are selected for plant type, and other important characteristics for progeny test, will enhance greatly the number of blast resistant lines that may be selected in the progeny test. However, this may require plenty of time and labor in sorting the individual resistant seedlings for planting which we are trying to avoid in the use of the bulk method. Since a large number of individual plants are selected for other important agronomic characters F 5 for the progeny test, we thought that we ·will aiso have a good chance of selecting lines with high resistance to blast.

\Vith adequate technical assistance and funds for labor, the suggestion will certainly be useful in improving the bulk method of selection for resistance to blast disease.

References for Paper 7

L Gcto, l\1. Resistance of rice varieties and species of wild rice to bacterial leaf blight and bacterial leaf streak diseases. The Philippine Agriculturist 48: 32~Hl38.

~2, Ou, S. H. Varietal reaction of rice to blast. Paper presented at the Symposium on Rice Blast Disease held July 7-12, 1963 at the I11ternational Rice Research Institute, Los Banos, Laguna, Philippines.

:3. Ou, S. H. Pathogenic races of Piricularia oryzae of the Philippines. (Mimeographed distributed by the IRRI to cooperating stations. 1964.)

4. Ou, S. H. and F. Nuque. 1963. The relation between leaf and neck resistance to the rice blast disea~e. International Rice Commission News Letter Vol. 12 (No. 4): p. 19-30.

5. Ou, S. H. 1966. International Uniform Blast Nurseries, 1964-·1965 results. International R.ice Commission News Letter Vol. 15: 3) p. 1··13.

6. Reyes, Gaudencio M. (1966) Progress of Applied Research in the Pathology of Rice. Two and a half decades of public service to philippine Agriculture. Bureau of Printing, Manila, 1956.

7. Reyes, Gaudencio M. and Benjamin Legaspi, 1959. Progress report on test for reaction of rice varieties to blast or rotten neck in tbe Philippines. Philippine Journal of Agricul­ture VoL 24: (Nos. 1-2) pp. 1-17, pl. 1·4; Fig. J .. 2.